"Microsoft's Surface Pro tablet, due on February 9th, will have a smaller amount of storage space than expected. A company spokesperson has confirmed to The Verge that the 64GB edition of Surface Pro will have 23GB of free storage out of the box. The 128GB model will have 83GB of free storage. It appears that the Windows 8 install, built-in apps, and a recovery partition will make up the 41GB total on the base Surface Pro model." Oh Microsoft.

As I said:
Win 8 x86 = 5 GB
Win 8 x64 = 8 GB
That difference is only partly because x64 binaries are bigger than x86 binaries. The real difference are all the bits and pieces that are present in both x64 and x86 despite http://en.wikipedia.org/wiki/WoW64.

I am a big Windows lover, but losing this much space is WAY over the top. I have less space left on a 64 GB Surface Pro than on a 32 GB iPad.

Just for experimenting I extracted the Windows 8 x64 Enterprise wim file to a 16 GB USB Stick (effectively creating a 16 GB Windows 8 To Go), booted from it, finished the installation, kept the default apps, installed drivers and Office and everything still worked. About 4 GB diskspace remaining, so all that is actually needed for a working Surface 8 Pro + Office 2013 is 12 GB.

If I can do it in half a day and with only the tools that are available by default in Windows 8 then Microsoft should be able to do a much better job